Composite quasi-particles with emergent functionalities in spintronic and quantum information science can be realized in correlated materials due to entangled charge, spin, orbital, and lattice degrees of freedom. Here we show that by reducing the lateral dimension of correlated antiferromagnet NiPS3 flakes to tens of nanometers, we can switch-off the bulk spin-orbit entangled exciton in the near-infrared (1.47 eV) and activate visible-range (1.8 to 2.2 eV) transitions with charge-transfer character. These ultra-sharp lines (<120 ueV at 4.2 K) share the spin-correlated nature of the bulk exciton by displaying a Neel temperature dependent linear polarization. Furthermore, exciton photoluminescence lineshape analysis reveals a polaronic character via coupling with at-least 3 phonon modes and a comb-like Stark effect through discretization of charges in each layer. These findings augment the knowledge on the many-body nature of excitonic quasi-particles in correlated antiferromagnets and also establish the nanoscale platform as promising for maturing integrated magneto-optic devices.
@article{arxiv.2306.02238,
title = {Correlated Excitonic Signatures in a Nanoscale van der Waals Antiferromagnet},
author = {Vigneshwaran Chandrasekaran and Christopher R. DeLaney and David Parobek and Christopher A. Lane and Jian-Xin Zhu and Xiangzhi Li and Huan Zhao and Cong Tai Trinh and Marshall A. Campbell and Andrew C. Jones and Matthew M. Schneider and John Watt and Michael T. Pettes and Sergei A. Ivanov and Andrei Piryatinski and David H. Dunlap and Han Htoon},
journal= {arXiv preprint arXiv:2306.02238},
year = {2023}
}